Tamper-indicating closure with resilient locking projections

ABSTRACT

A method for manufacturing a tamper-indicating closure having a plurality of resilient flexible projections bent upwardly and radially inwardly at a predetermined radius of curvature. The first step in the method includes providing a mold assembly comprising a female mold portion for forming the outer surface of the closure and a male mold portion for forming the closure&#39;s inner surface and its plurality of projections. The male and female mold portions are arranged for relative movement toward and away from each other between a mold open position and a mold closed position. When in the mold closed position, the male and female mold portions define a mold cavity in which the tamper-indicating closure is molded. The next steps in the method are to move the male and female mold portions into the mold closed position; to provide a mold material into the mold cavity; and, to maintained the mold portions in the mold closed position for a predetermined time period until the tamper-indicating closure is formed with its projections disposed at their predetermined radius of curvature. Next, the male mold portion is removed from the molded closure, whereby the projections temporarily bend from their predetermined radius of curvature to a second position. The closure includes a plurality of strain relief recesses corresponding to the number of projections, each strain relief recess being located radially outwardly from each projection. Each recess, in combination with the predetermined radius of curvature, acting to limit the extent of deformation of the corresponding projection during removal of the male mold portion so the projection can elastically return to substantially its “as molded” configuration.

RELATED APPLICATION

This application is a Divisional of application Ser. No. 09/656,597,filed Sep. 7, 2000, now U.S. Pat. No. 6,355,201, entitledTamper-Indicating Closure With Resilient Locking Projections, thedisclosure of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

This present invention relates generally to a tamper-indicating closureand a method for manufacturing that closure. More particularly, thepresent invention relates to a tamper-indicating closure having aplurality of locking projections that are molded to extend from thetamper-indicating ring radially inwardly and upwardly at a predeterminedradius of curvature. After molding, during removal of a male coreportion from the molded closure, the projections temporarily benddownwardly from their predetermined radius of curvature. A strain reliefrecess, located radially outwardly from the locking projections,substantially reduces the extent of plastic deformation of theprojections during removal of the male core portion. Thus, followingremoval of the male core portion, the projections elastically return tosubstantially their predetermined radius of curvature. Because theprojections are able to elastically return, secondary heating andphysical manipulation steps are eliminated.

It is important to provide tamper-indicating features on bottles andother containers. Increasingly, consumers have come to expect containersof all types that contain substances for human consumption to beequipped with tamper-indicating features. Although the use of suchclosures is widespread, the expense involved in producing suchtamper-indicating closures has limited their use. If tamper-indicatingclosures could be manufactured less expensively than under currentmethods, they would be even more widely used.

One approach to providing a tamper-indicating closure is to provide anupper cap portion and a lower tamper-indicating ring which is detachablyconnected to the cap portion by a failure line. Under this approach,typically, constructions employ a plurality of resilient flexibleprojections or fingers which extend upwardly and radially inwardly fromthe lower tamper-indicating ring. Once the closure is applied to thecontainer neck, these upwardly and inwardly directed projections move toengage an annular locking ring portion located on the container neck.When the closure is unscrewed from the neck of the container, thetamper-indicating ring becomes detached from the cap portion and remainson the container neck. Thus, when the cap portion is replaced on thecontainer neck, an identifiable gap forms between the cap portion andthe tamper-indicating ring which serves as a visual indication that thecontainer has been previously opened.

Previous molding processes that have been used to manufacturethermoplastic tamper-indicating closures did not mold the projections intheir final upward and radially inward positions. This is due to thefact that once the tamper-indicating closure is formed between femaleand male mold portions, it was necessary to remove the male mold portionfrom within the formed closure. If the projections were molded in theirfinal upward and radially inward positions beneath the male moldportion, removal of the male mold portion from within the closure wouldcause these projections to bend severely and break off from thetamper-indicating ring. Instead, under these previous molding processes,closures were molded having projections that point straight down in anunbent fashion. In this manner, bending and breaking off of theprojections during removal of the male mold portion was avoided.However, after removal of the male mold portion, post-forming operationsbecame necessary to bend the projections upwardly to their final upwardand radially inward positions. Due to the memory nature of thermoplasticmaterials, it was then necessary for the projections to be heated tore-set them from their straight down unbent configuration to their finalupward and radially inward orientation. These post-forming stepsincrease manufacturing costs and cycle time. Additionally, thesepost-forming steps introduce unwanted variability into the manufacturingprocess. As a result, tamper-indicating closures manufactured utilizingthese post-forming steps are costly and yield a product that is notsufficiently uniform in configuration.

Thakor et al. (U.S. Pat. No. 5,846,471) discloses a method and apparatusfor manufacturing a tamper-indicating closure whereby thetamper-indicating projections are molded in their final position toextend radially inward and upward. Upon removal of the male mold portionfrom the closure, the plurality of projections must bend downwardly to adegree that is substantially parallel to the longitudinal axis of theapparatus. Such a degree of downward bending subjects the projections tosignificant deformation which prevents these projections from returninganywhere near their final orientation after removal of the male moldportion. Rather, under Thakor et al., after removal of the male moldportion, the projections bend inwardly to a position that is somewhereintermediate between straight down, unbent and their final moldedorientation. Thus, after removal of the male mold portion, in order toreturn the projections to their final molded orientation, i.e., upwardand radially inward, it is necessary to perform a secondary operationwhereby the male mold portion is utilized to physically urge thedownwardly bent projections to their originally molded position.Apparently, because the projections were molded in their final formrather than pointing straight down, no heating step is necessary to setthe projections in their final orientation. Although Thakor et al.,appears to be an improvement over the prior art molding processesdiscussed above because it apparently has eliminated a heating step,there still remains a post forming step which is required to urge thedeformed projections to their originally molded orientation

It is an object of the present invention to overcome these drawbacks andto provide a method for producing a tamper-indicating closure havingresilient projections which elastically return substantially to theirfinal position after removal of the male mold portion. The inventiveclosure requires no post forming operations such as physicalmanipulation or heating as discussed above.

OBJECTS OF THE INVENTION

Accordingly, it is a general object of this invention to provide aunitary tamper-indicating closure with resilient locking projectionsthat overcomes the disadvantages of prior art.

It is a more specific object of this invention to provide a unitarytamper-indicating closure with resilient locking projections that has ahigh durability and long life span.

It is a more specific object of this invention to provide a unitarytamper-indicating closure with resilient locking projections thateliminates secondary heating and physical manipulation steps during themanufacturing process resulting in less manufacturing costs.

It is also a specific object of this invention to provide a unitarytamper-indicating closure with resilient locking projections which issimple in construction.

It is also a specific object of this invention to provide a unitarytamper-indicating closure with resilient locking projections which isreliable in operation and easy to use.

SUMMARY OF THE INVENTION

These and other objects of this invention are achieved by providing amethod for manufacturing a tamper-indicating closure having a pluralityof resilient flexible projections bent upwardly and radially inwardly ata predetermined radius of curvature. The first step in the methodincludes providing a mold assembly comprising a female mold portion forforming the outer surface of the closure and a male mold portion forforming the closure's inner surface and its plurality of projections.The male and female mold portions are arranged for relative movementtoward and away from each other between a mold open position and a moldclosed position. When in the mold closed position, the male and femalemold portions define a mold cavity in which the tamper-indicatingclosure is molded. The next steps in the method are to move the male andfemale mold portions into the mold closed position; to provide a moldmaterial into the mold cavity; and, to maintain the mold portions in themold closed position for a predetermined time period until thetamper-indicating closure is formed with its projections disposed attheir predetermined radius of curvature. Next, the male mold portion isremoved from the molded closure, whereby the projections temporarilybend from their predetermined radius of curvature to a second position.The closure includes a plurality of strain relief recesses correspondingto the number of projections, each strain relief recess being locatedradially outwardly from each projection. Each recess, in combinationwith the radius of curvature, acting to limit the extent of permanentdeformation of the corresponding projection during removal of the malemold portion so the projection can elastically return to substantiallyits “as molded” configuration.

In a variation of the disclosed embodiment, the male mold portioncomprises an inner core member, a skirt member and an outer core member.The resilient flexible projections of the closure are formed between amolding surface disposed on the outer core member and a molding surfacedisposed on the skirt member. Prior to the step of removing the malemold portion from the molded tamper-indicating closure, the methodfurther includes the step of separating the molding surface disposed onthe outer core member from the bottom surface of the closureprojections.

In another variation of the disclosed embodiment, following the step ofseparating the molding surface of the outer core member from the bottomsurface of the closure projections, the method further includes the stepof separating the female mold portion from the molded tamper-indicatingclosure.

In another variation of the disclosed embodiment, the inner surface ofthe closure includes an integrally molded internal screw thread arrangedfor engagement with an external screw thread disposed on the inner coremember. The mold assembly includes a stripper ring arranged to bepositioned against the closure to resist rotational movement of theclosure during removal of the male mold portion. Under this variation,the step of removing the male mold portion from the closure includes thesub-step of rotating the inner core member while utilizing the stripperring to maintain the closure non-rotational which causes the inner coremember to unscrew from the closure.

In another variation of the disclosed embodiment, the mold assemblyadditionally comprises a knock-out bar arranged for movement between aretracted position to an extended position. Following the step ofremoving the male mold portion from the molded tamper-indicatingclosure, the method comprises the additional step of moving theknock-out bar from the retracted position to the extended position toeject the closure from the stripper ring.

DESCRIPTION OF THE DRAWINGS

Other objects and many attendant features of this invention will becomereadily appreciated as the same becomes better understood by referenceto the following detailed description when considered in connection withthe accompanying drawings wherein:

FIG. 1 is an isometric view of the tamper-indicating closure withresilient locking projections of the present invention;

FIG. 2 is a sectional view taken through line 2—2 of FIG. 1;

FIG. 3 is a bottom view of the tamper-indicating closure of the presentinvention;

FIG. 4A is a sectional view a projection of the tamper-indicatingclosure, the projection shown in its upward and radially inwardorientation after removal of the male mold portion;

FIGS. 4B through 4D are three sectional views of a projection of thetamper-indicating closure, the projection being deflected progressivelydownwardly from its molded position to a vertical downward orientation(illustrated in FIG. 4D) during removal of the male mold portion;

FIG. 5 is a cross-sectional view of the molding apparatus of the presentinvention shown in a closed position;

FIG. 5A is a detailed view of the area circled and labeled “FIG. 5A” inFIG. 5;

FIG. 6 is a cross-sectional view illustrating a second movement of themolding apparatus of the present invention wherein the outer core memberis separated from the bottom surfaces of the projections of theinventive tamper-indicating closure;

FIG. 6A is a detailed view of the area circled and labeled “FIG. 6A” inFIG. 6;

FIG. 7 is a cross-sectional view illustrating a third movement of themolding apparatus of the present invention wherein the female portion ofthe mold cavity is removed from the outer surface of the inventivetamper-indicating closure and the inner core member and skirt member areremoved from within the tamper-indicating closure;

FIG. 7A is a detailed view of the area circled and labeled “FIG. 7A” inFIG. 7;

FIG. 8 is a cross-sectional view illustrating a fourth movement of themolding apparatus of the present invention wherein a knock-out bar movesupwardly to eject the tamper-indicating closure from the stripper ring;and,

FIG. 8A is a detailed view of the area circled and labeled “FIG. 8A” inFIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the various figures of the drawing wherein likereference characters refer to like parts, there is shown at 10 in FIGS.1 through 3, a tamper-indicating closure having resilient lockingprojections that has been molded in accordance with the presentinvention. The closure of the present invention is intended forplacement over and securement to a container having an externallythreaded neck. The closure 10 includes an internally threaded upper capportion 12 and a lower tamper-indicating band or ring 14 which isdetachably connected to the cap portion 12 by a failure line or area ofweakness. The cap portion 12 includes a top wall 16 for extending acrossthe open top of a container and an annular skirt or sidewall 18integrally joined to the top wall 16 about the periphery of the top walland having a screw thread 21 (FIG. 2) formed on its inner surface forengagement with a threaded container neck (not shown). Together, the topwall 16 and the side wall 18 form the cap portion 12. As best shown inFIG. 4A, the tamper-indicating ring 14 is detachably connected to thelower periphery of the sidewall by breakable connector means 20. Thebreakable connector means 20 could be further weakened by the inclusionof series of generally rectangular perforations (not shown) cut into thebreakable connector means 20 at evenly spaced intervals about thecircumference thereof. When the cap portion 12 is unscrewed from thecontainer neck (not shown), the tamper-indicating ring 14 is retained onthe container neck by an annular container shoulder (not shown) andbreaks away from the cap portion 12.

As best shown in FIGS. 2, 3 and 4A, a tamper-indicating closure 10 isprovided with moveable, resilient projections 22 formed of any suitablethermoplastic material which lock against the lower surface of theannular container shoulder (not shown) to retain the tamper-indicatingring 14 on the container neck (not shown) as the cap portion 12 isremoved. The preferred projections 22 are integral with the ring 14 andextend radially inward and upward from the generally cylindrical ring14. As the cap portion 12 is removed, the upward force on thetamper-indicating ring 14 tends to bow the projections 22 inwardlyagainst the annular container shoulder (not shown) and to stiffen theprojections 22 to cause them to engage more tightly and to grip thecontainer neck. The tamper-indicating ring 14 slides a short distancedown the neck of the container after being broken away from the capportion 12 so that after replacement of the cap on the container, thereremains a readily discernible visual indication that the container hasbeen opened.

Turning now to a more detailed description of a preferred embodiment ofthe closure 10 of the present invention, the cap portion 12 andtamper-indicating ring 14 herein are made of a moldable plasticmaterial, such as polypropylene. As best seen in FIG. 1, the closureskirt or sidewall 18 has a generally cylindrical exterior with aplurality of equally spaced vertical ribs 28 formed to facilitategripping of the cap.

As shown in FIG. 2, the tamper-indicating ring 14 is connected to thecap portion 12 by a breakable connector means 20 which is preferablylocated immediately below the lower end of closure sidewall 18. Thebreakable connector means 20 is a weakened area that provides a severingplane normal to the closure 10 central axis at which thetamper-indicating ring 14 will consistently detach from the cap portion12 when the closure 10 is unscrewed. The breakable connector means 20may be made in various manners. In other words, the breakable connectormeans 20, as illustrated in FIG. 2, could be constructed in a variety ofother ways without departing from the scope of this invention. Forinstance, in accordance with the present invention, the breakableconnector means 20 could be further weakened by the addition of aplurality of generally rectangular perforations (not shown) that are cutinto the connector means 20 at evenly spaced intervals about thecircumference thereof. These perforations could be added in a secondaryoperation following molding of the inventive closure 10. Theperforations (not shown) could be of any suitable dimension, e.g., 0.125inches in length, and may be separated from each other by any suitabledistance, e.g., a 0.020 inch web disposed therebetween.

Referring now to FIG. 4A, there is shown therein a cross-sectional viewof one of the projections 22 of the tamper-indicating closure 10 of thepresent invention molded in its final upward and radially inwardorientation.

Turning now to a description of the method of the present invention, theclosure 10 of the present invention is formed under the followingmethod. FIGS. 5 through 8 and FIGS. 5A through 8A illustratecross-sectional views of a molding apparatus 50 of the present inventionfor manufacturing a tamper-indicating closure 10 that is provided with aplurality of projections 22 extending radially upward and inward from atamper-indicating ring 14 of the closure 10. Although for the sake ofsimplicity the present discussion focuses on the capability of themolding apparatus 50 to manufacture the tamper-indicating closure 10shown in FIGS. 1 through 3, it is to be understood that the presentinvention has the ability of being modified to produce other types oftamper-indicating closures having projections that are to be formed invarious configurations.

FIGS. 5 and 5A illustrate the molding apparatus 50 in the mold closedposition, in which the apparatus 50 is configured to receive from aninjection port 52 molten plastic material into a mold cavity 54, Asshown in FIGS. 5 and 5A, the mold cavity is shown filled with plasticmaterial forming the closure 10 of the present invention. Referring nowto FIG. 5A, the mold cavity 54 is defined as the volume of spaceexisting between the outer surface of a moveable male mold portion 56and the inside surfaces of a female mold portion 58. The female moldportion 58 comprises an annular recess 59 (best shown in FIGS. 7 and7A), the inner surface of which comprises a mold surface for forming theouter surface of the top wall 16, the outer surface of the annularsidewall 18 and the outer surface of the tamper-indicating ring 14 ofthe closure 10.

Referring again to FIG. 5A, the male mold portion 56 is referred to asmoveable because, as shall be explained later, the male mold portion 56may be moved along a longitudinal axis of the apparatus 50. The moveablemale mold portion 56 comprises an inner core member 60, a skirt member62 and an outer core member 64. The inner core member 60 has anexternally threaded outer side surface 66, for forming the internalscrew thread 21 (FIG. 2) formed on the inner surface of the sidewall 18of the closure 10.

The skirt member 62 includes a bottom molding surface 62 a and the outercore member 64 includes a top molding surface 64 a. Together, thesemolding surfaces 62 a and 64 a define a portion of the mold cavity 54therebetween in which the projections 22 of the closure 10 are formed intheir final, radially upward and inward position. The angle ofinclination of surfaces 62 a and 64 a can be configured to any desiredinclination, and this angle of inclination corresponds to the degree towhich the projections 22 extend radially upward and inward from thetamper-indicating ring 14 of the closure 10. In addition, the angle ofinclination of surfaces 62 a and 64 a, relative to one another, may bevaried to create projections which vary in thickness along their length.As best shown in FIGS. 4A through 4D, the thickness of the projection 22increases as the projection extends upwardly and radially outwardly.

As best shown in FIG. 5A, the closure 10 of the present invention isshown disposed within the mold cavity 54 and is comprised of theelements mentioned earlier, i.e., a top wall 16, an annular sidewall 18,a tamper-indicating ring 14 and a plurality of projections 22. Themovable male mold portion 56 further includes a central bore that hastwo open ends and that is substantially axially aligned with thelongitudinal axis of the apparatus 50. This bore receives a knock-outbar 70 that slidably engages the inner surface of the bore. In the moldclosed position, the outer surface of the movable male mold portion 56is maintained at a predetermined distance from the inner surface of theannular recess 59 of the female mold portion 58 so that the spacebetween the outer surface of the movable male mold portion 56 and thesurface of the annular recess 59 of the female mold portion 58 forms alarge portion of the mold cavity 54.

In the mold closed position of the apparatus 50, the top surface 76 ofknock-out bar 70 is aligned to be at the same height as the top surface74 of the movable male mold portion 56. When the molding material,usually molten plastic, is injected into the mold cavity 54 from theinjection port 52, the top surface 74 of the movable male mold portion56, in cooperation with the top surface 76 of the knock-out bar 70,forms the top wall 16 of the closure 10.

As stated before, movable male mold portion 56 includes an axiallyaligned bore having two open ends for receiving the knock-out bar 70. Inorder to form the closure 10, the apparatus is set to the mold closedposition. Molding material is then introduced into mold cavity 54 by theinjection port 52. When the molding material has hardened sufficiently,a closure 10 having an internally threaded cap portion 12, a cylindricaltamper-indicating ring 14, and a plurality of projections 22 extendingradially inward and upward from the tamper-indicating ring 14 is formed.As illustrated in FIG. 5A, the projections 22 extend in their finalmolded position radially inward and upward from the tamper-indicatingring 14. FIGS. 6 through 8 and FIGS. 6A through 8A illustrate thevarious operations that the apparatus 50 performs in order to eject theformed closure 10 from the mold cavity 54 while preserving the desiredmolded configuration of the projections as shown in FIG. 4A.

Referring now to FIGS. 6 and 6A, after the closure 10 has solidified butnot necessarily cooled completely, the outer core member 64 is movedaway from the remaining components of the moveable male mold portion 56.That is, the outer core member 64 is moved away from the skirt member 62and the inner core member 60. This operation exposes the lower wall 22 a(best shown in FIG. 6A) of each of the projections 22.

Next, as shown in FIGS. 7 and 7A, the female mold portion 58 is liftedaway from the closure 10. Thus, the annular recess 59 is lifted toexpose the outside surfaces of the top wall 16 and annular sidewall 18of the closure 10. With the female mold portion 58 lifted away, the nextstep in the process is to unscrew the inner core member 60 and skirtmember 62 from within the closure 10. FIGS. 7 and 7A illustrate theinner core member 60 and the skirt member 62 after they have beenunscrewed and withdrawn vertically downwardly from within the closure10. A stripper ring 119, having a plurality of upwardly extending offingers (not shown), surrounds the tamper-indicating ring 14 of theclosure 10. The plurality of upwardly standing metal fingers (not shown)disposed on the stripper ring 119 extend into pockets 27 located betweenthe projections (best shown in FIG. 3) on the closure. Because theupwardly projecting fingers (not shown) extend into the pockets 27, thestripper ring 119 remains affixed to the closure 10 and preventsrotational movement of the closure 10 during the unscrewing of the innercore member 60 and skirt member 62.

During removal, the inner core member 60 and the skirt member 62 arerotated and moved downwardly along the longitudinal axis of theapparatus 50. Since the stripper ring 119 ensures that the closure 10remains non-rotational, rotation of the inner core member 60 and skirtmember 62 causes these members to be unscrewed from the closure 10. Asthe inner core member 60 and skirt member 62 move away from the closure10, the vertical sidewalls of the inner core member 60 and skirt member62 urge the projections 22 to temporarily point downwardly in analignment substantially parallel to the longitudinal axis of theapparatus 50. This progressive movement of the projections 22 from theirposition as molded to pointing vertically downwardly during removal ofthe inner core member 60 and skirt member 62 is best illustrated inFIGS. 4A through 4D.

FIG. 4A illustrates a projection 22, as molded, extending radiallyinwardly and upwardly from the tamper-indicating ring 14 at apredetermined angle of inclination, that angle being indicated at 15 andat a predetermined radius of curvature. The predetermined angle ofinclination, indicated at 15, is measured from the vertical inside wallof the ring 14 and is any suitable angle, e.g., between 20° and 75°. Solong as the projection 22 does not extend below the bottom horizontalplane 19 of the closure 10, after removal of the male mold portion 56,the closure 10 is acceptable for use. However, the angle of inclinationillustrated in FIG. 4A is preferable. The radius of curvature 23 may beany suitable dimension, e.g., 0.030 inches where the overall diameter ofthe closure is approximately 0.870 inches. As the overall diameter ofthe closure 10 increases, the radius of curvature 23 may be increased.As explained previously, the projections 22 should point radially upwardas well as inward so that the projections can be urged against the lowersurface of the annular shoulder of the container when the cap portion isunscrewed from the container. As shown in FIGS. 4A through 4D, theprojections 22 may also increase in thickness as they extend from theirradius of curvature 23 upwardly and inwardly to occupy more spacebeneath the lip of the bottle. At the bottom of the radius of curvature23, the projection may be of any suitable thickness that providessufficient strength, flexibility and recoilability, e.g., a thicknessbetween about 0.018 and about 0.019 inches. As opposed to a sharp bend,the radius of curvature 23 is provided to enable the projections 22 toroll out in a gradual manner during removal of the inner core member 60and the skirt member 62 to minimize the occurrence of any plasticdeformation.

The tamper-indicating ring 14 is also provided with a strain reliefrecess 25 which acts to reduce plastic deformation of each projection 22as each is temporarily bent downwardly from its molded orientationthrough the increasing amounts of deflection as illustrated in FIGS. 4B,4C and 4D during removal of the inner core member 60 and skirt member62. The strain relief recess 25 may be of any suitable dimensions. Asshown in FIG. 4A, the strain relief recess 25 includes an apex 29. Therecess 25 should be formed in any manner such that the thickness ofmaterial at the bottom of the radius of curvature 23 is maintainedconstant as the curvature extends from the bottom of the radius ofcurvature 23 to the apex 29. By maintaining the thickness in this area,compression of material is avoided to minimize plastic deformation andsubstantially reduce the possibility of breakage of the projectionsduring removal of the inner core member 60 and skirt member 62.

FIGS. 4B, 4C and 4D illustrate the manner in which each projection 22 istemporarily bent downwardly from its molded orientation as the innercore member 60 and skirt member 62 are moved further downwardly alongthe longitudinal axis of the apparatus 50 from within the closure 10. InFIG. 4B, the inner core member 60 and skirt member 62 have only beenmoved downwardly from within the closure 10 by a small amount. Thus, theprojection 22 has begun to bend by only a small amount. This amount ofdownward deflection is within the elastic limit of the projection 22 anddoes not result in the projection 22 being plastically deformed in amanner that would prevent it from bending back to its “as molded”position. That is, if the extent of bending of the projections 22 wereas shown in FIG. 4B, upon removal of the bending force, the projection22 would return fully to its “as molded” position as shown in FIG. 4A.Referring now to FIG. 4C, as the inner core member 60 and skirt member62 are removed further downwardly from the closure 10, the projection 22is bent an even greater amount to a point which represents the elasticlimit of the projection 22. In other words, if the projection 22 werebent only to the point as shown in FIG. 4C, upon removal of the bendingforce, the projection 22 would bend back fully to its “as molded”orientation as shown in FIG. 4A because the projection 22 has not lostany of its resiliency due to plastic deformation. Further bending beyondthe elastic limit (FIG. 4C) causes the projection 22 to undergo plasticdeformation, as shown in FIG. 4D. As shown in FIG. 4D, upon removal fromthe closure 10, the sidewalls of the inner core member 60 and skirtmember 62 cause the projections 22 to be bent to a position where theyare in vertical alignment with the longitudinal axis of the apparatus50. In this position, the projections 22 undergo some degree of plasticdeformation. However, as explained below, the provision of the strainrelief recess 25 enables each projection 22 to retain substantially allof its resiliency so that after removal of the inner core member 60 andskirt member 62, the projections 22 bends back to substantially its “asmolded” position.

The strain relief recess 25 provides an area into which thethermoplastic material of the projection 22 can flow during deflectionto minimize plastic deformation. A comparison of the size and shape ofthe strain relief recess 25 as illustrated in FIGS. 4B, 4C and 4Dreveals that as the projection 22 is bent further downwardly, itsassociated strain relief recess 25 grows smaller. The ability of thestrain relief recess 25 to take up thermoplastic material as theprojection 22 is bent reduces compression of thermoplastic material inthe area of the radius of curvature 23 and enables the projection 22 tobe bent further before the occurrence of plastic deformation. In thismanner, the amount of plastic deformation resulting from bending theprojection 22 to the position shown in FIG. 4D is minimized, thusenabling the projection to return substantially to its original “asmolded” position as shown in FIG. 4A although the inclination of theprojection 22 may differ to a nominal extent due to plastic deformation.Under the prior art methods discussed above that do not provide either aradius of curvature 23 or a strain relief recess 25, or both, theperformance of one or more secondary operations would be necessary toheat and/or physically urge the downwardly bent projections from theirposition as shown in FIG. 4D to their “as molded” position as shown inFIG. 4A.

Referring now to FIGS. 8 and 8A, under the final step, the knock-out bar70 is moved through the bore of the moveable male mold portion 56 toeject the closure 10 out of the stripper ring 119. With the closure 10ejected and conveyed out of the apparatus 50 to a receiving bin, theapparatus moves back to the closed position as illustrated in FIGS. 5and 5A to repeat the process detailed above. Thus, the present inventionenables the manufacture of a closure 10 having projections 22 thatextend radially inward and upward from a tamper-indicating ring 14 ofthe closure 10 without relying on any secondary steps necessary to bendand set the projections into the desired configuration.

Those skilled in the art will understand that there are manymodifications which may be made to the disclosed embodiments withoutdeparting from the teachings of the invention and these modificationsare considered to be within the scope of this invention which isintended to be limited only by the claims appended hereto.

I claim:
 1. A tamper-indicating closure having a plurality of resilientflexible projections, said closure being formed within a mold assemblycomprising a male mold portion and a female mold portion, the male moldportion initially being disposed within said closure for forming theinner surface of said closure, the female mold portion constructed toform the outer surface of said closure, the male mold portion beingremoved from within said closure during a subsequent molding step, saidclosure comprising: a. a cap portion; b. a tamper-indicating ringdepending from said cap portion, c. a plurality of separate resilientflexible projections depending from a lower region of said ring, saidseparate projections bending upwardly and radially inwardly at apredetermined radius of curvature from said ring, said separateprojections each being moveable around a respective horizontal axis; d.each of said separate projections having a corresponding separatedownward-motion deformation-limiting strain relief recess formed in saidring, each separate downward-motion deformation-limiting strain reliefrecess being disposed radially outwardly from its corresponding separateprojection of plurality of separate projections to limit the extent ofplastic deformation of said separate projections when a downward-motionproducing force is applied to said projections and said projections arebent downwardly around their horizontal axis from their predeterminedradius of curvature to a second position during removal of the male moldportion from within the tamper-indicating closure during the subsequentmolding step, said separate downward-motion deformation-limiting strainrelief recesses enabling their corresponding separate projections toelastically return to substantially their predetermined radius ofcurvature.
 2. The tamper-indicating closure of claim 1 wherein saidradius of curvature is approximately 0.030 inches.
 3. Thetamper-indicating closure of claim 1 wherein the thickness of each saidprojection is between about 0.018 and about 0.019 inches.
 4. Thetamper-indicating closure of claim 1 wherein said plurality of resilientflexible projections comprises three or more resilient flexibleprojections is located at an equal circumferential interval about saidring.
 5. The tamper-indicating closure of claim 1 wherein said pluralityof resilient flexible projections are disposed at an angle ofinclination of approximately 20°.
 6. The tamper-indicating closure ofclaim 1 wherein said plurality of resilient flexible projections aredisposed at an angle of inclination of between about 20° and 70°.